RIO DE JANEIRO, Aug. 26 (Xinhua) -- The run for Brazil's presidency has seen a significant shift in the past two weeks, with newly-named candidate Marina Silva ranked second, said a poll released Tuesday,

According to the survey by pollster Ibope, President Dilma Rousseff, who is running for reelection as the candidate of a Workers' Party-led coalition, is still in the lead with 34 percent of the vote.

Newcomer Silva, of the Brazilian Socialist Party (PSB), has 28 percent support, and Aecio Neves, of the conservative Brazilian Social Democracy Party (PSDB), has 19 percent.

Eight other candidates account for 3 percent of the votes between them, while 7 percent of voters were still undecided and 8 percent planned to vote blank.

The figures represent a significant change in the race since Eduardo Campos, candidate for PSB, died in a plane crash while campaigning and Silva was tapped to replace him.

In the last poll before his death, Campos trailed in distant third place with 9 percent of the votes, meaning support for the PSB has grown threefold due to Silva.

Silva has now significantly more support than she had in the 2010 presidential race, when she ranked third, with 19 percent of the votes.

According to Ibope, the poll for the first time showed an opposition candidate with a clear chance to win in a possible runoff.

In a runoff between Rousseff and Silva, Silva could win by a clear majority of 45 percent versus Rousseff's 36 percent, said Ibope.

In a runoff between Rousseff and Neves, the president could win 41 to 33 percent.

Rousseff additionally has the highest rejection rate of all the candidates, with 36 percent, compared to Neves' 18 percent and Silva's 10 percent.

Shortly after Campos' death, Neves attributed Silva's rise to the reactions surrounding her running mate's sudden death. Earlier this week, he likened her progress in the polls to a wave in the sea.

The Ibope poll, carried out from Aug. 23-25, surveyed 2,506 people in 175 towns across Brazil, and has a margin of error of two points.